Babies learn about their new world through sensory exploration. Apart from learning through the ear by listening to mums voices, newborn babies also learn their new world through vision. The eyes and the visual cortex of infants continue to develop after birth according to how much stimulation the babies receive. Research has increasingly acknowledged the importance of multisensory interactions in early child development, and the topic of auditory-visual integration becomes critical for early childhood learning programs.
Sensory integration is the neurological process, which deals with how the brain processes sensory input from multiple sensory modalities, including sight, hearing, touch, smell, and taste, and are subject to critical periods. The sense of baby’s hearing develops much before the birth of the baby. The sense of smell is the most advanced out of the five senses. The sense of touch and the sense of taste are also well-developed considerably in infants, but the sense of vision is under-developed at birth. At birth, an infant’s vision is blurry and sees things only in black and white, but in just two weeks time, the baby acquires the ability to distinguish bright colors. By two to three months old, baby’s vision equates to the other senses, and the color vision becomes similar to that of adults.
Though the sense of vision is immature at birth, the effect of heteromodal stimuli advances baby’s visual development. It has been reported, as early as 1933 by G. W. Hartmann, that visual acuity can be increased by the simultaneous application of auditory, olfactory, and cutaneous stimuli. High and low tones, pleasant and unpleasant odors, mild tactile and painful stimuli, all enhance the discrimination of black-on-white or white-on-black configurations. Learning and neural plasticity in early life are highly multisensory. As testified by thousands of parents who teach their babies to read with Doman method, a well designed auditory-visual display to young children creates simultaneous visual and auditory stimulations, which advance children’s neurosensory development as well as cognitive development, thanks to intersensory facilitation.